Muscle Molecule Spurs Fat Cells to Slim Down

How your body turns the pain of exercise into the gain of health benefits has become a bit clearer, thanks to a new discovery: When you work out, your muscles release a molecule that modifies fat cells.

The protein PGC-1α helps orchestrate the body's response to exercise. But because it doesn't travel outside muscle cells, researchers have been hunting for its molecular emissaries. Now, Robert Gerszten of Harvard Medical School in Boston and colleagues have found that PGC-1α–making muscle cells secrete a messenger called β-aminoisobutyric acid (BAIBA).

BAIBA induces energy-storing white fat cells to become more like brown fat cells, which burn calories, the researchers report this week in Cell Metabolism. Mice that lapped up water laced with BAIBA lost weight and showed other metabolic benefits. The researchers also found low BAIBA levels in subjects from the famous Framingham Heart Study who had risk factors for heart disease and diabetes. Gerszten and colleagues intend to further study BAIBA in animals, and we may soon know whether it can deliver gain without the pain. http://scim.ag/BAIBA

Bacteria Tell Tubeworms Where to Settle

For their first few days of life, the larvae of the ocean-dwelling tubeworm Hydroides elegans drift over the sea floor in search of a home. The signal that causes them to settle down and take on their adult tubular form has long been mysterious. New research shows how bacteria on the ocean floor—or on the hulls of ships—play a role.

Biologists knew that the presence of certain bacteria growing on a surface helps trigger a larva's decision to settle and metamorphose, but no one could explain how bacteria prompt this. Online this week in Science, researchers report that the bacterial cells release elaborate structures resembling bits of viruses called phages, which link to form a 3D net. Touching the net prompts the larvae to attach to a surface (whether a rock or a ship's hull) and become adults. The discovery might lead to new ways to discourage tubeworms and other organisms from taking up residence on ship hulls. Such biofouling costs the shipping industry billions of dollars each year. http://scim.ag/_tube